Hips are the external angles made by the junction of the roof and its return round the ends, where the end walls are not carried up to the underside of the rake of roof to form gabks, as fig. 393.
Valleys are the converse of hips, and jack rafters are the short rafters which run between the hips or valleys and the wall-plates.
Dormers are gables on a small scale, or vertical windows placed on the inclined plane of a roof.
Fig. 394 illustrates a returned roof, with hips and a valley, showing generally the positions of some of the parts hereinbefore described, as particularised in the accompanying reference - viz., A, valley; B, hip; C, jack rafters; D, ridge; E, eaves; F, common rafters; G, gable; H, dormer; P- purlins; W, wall-plate.
Hips, on account of their great length, are sometimes made the principal rafter of half-trusses, which are bolted with angle irons to the king-posts of the main trusses, as at X, on fig. 395; and they are framed at the external angles into dragons, D, which are halved over the angle of the two wall-plates, W, and "tusk-tenoned" into an angle-braa, A, which stretches from wall-plate to wall-plate, forming an equilateral triangle with them. Fig. 396 is a plan and fig. 397 a section explaining the foregoing details.
Valleys are treated in a similar way, but being internal angles, have often to be covered with lead, which means boarding as a foundation, as fig. 398.
Instead of valley-rafters one roof is sometimes run through, and a valley board put on it, from which the short or jack rafters spring to the ridge, as fig. 399.
The eaves of roofs are at the feet or bottom of the rafters, where all the rain-water is collected into cast-iron gutters, hanging over the walls, from which it is taken by cast-iron downpipes to the drains below.
Fig. 400 represents an overhanging eaves with a fascia, F, fixed to the feet of the rafters, for carrying the cast-iron moulded guttering, G; while fig. 40 r shows the same fixed to a wood cornice.
Fig. 402 represents a cast-iron half-round gutter, fixed by wrought hanging irons to the wrought and cut rafter feet; these irons can also be fixed on the top of the rafters, but they are awkward if the gutter should afterwards have to be altered, necessitating taking off a few courses of the slates or tiles to get at them.
Fig. 403 represents the same, but the gutter is carried by wrought-iron brackets, fixed to the walls, which looks clumsy in work.
Gutters - i.e., those boarded and lead-lined - are laid either behind parapets and chimneys, or between M roofs. They should never be narrower than 9 inches at the bottom or starting-point, should rise about 1 1/2 inches in no more than 10 feet lengths, at the outside, and between each 10 feet, or less length, there should be a 2-inch drip, to give the water an impetus, and also to allow the plumbers to joint their lead. It should be borne in mind, in arranging the drips, etc., of gutters, that the sun interferes with lead when in long lengths, so that drips should be placed within the 10-feet limit where practicable.
Fig. 404 represents the plan of a lead gutter between two roofs, M, and fig. 405 a longitudinal section.
Fig 407. Section CD.
Fig. 406 is a cross-section of such a gutter, and fig. 407 an enlarged longitudinal section through a 2 inch drip.
It is always better to nail a feather-edged fillet on the face of the drip, to make the angle the more obtuse for dressing the lead over, as fig. 408. Moreover, care should always be taken that the boards carrying the lead are laid in the direction of the fall, and not crosswise.
The kar-boards and tilter are also fixed at the top return, X, fig. 406, as at the sides.
Cesspools are sunk boxes, placed at the lowest points, to collect the water previous to discharging it, through a pipe fitted to the bottom of the cesspool, into the rain-water pipe, or, better still, into a head connected to the downspout (fig. 409). The heads allow of the lead bend to the cesspool being open at both ends and accessible, which is a great convenience when they get stopped up with leaves - a very common occurrence. It is more convenient to have spout troughs through the walls from cesspool to head, when circumstances will allow of it.
Fig. 409. Section at Cesspool.
The position of these cesspools has to be regulated, of course, to suit the elevations of the building and the position in which the downpipes can be placed.
The angles of cesspools, as well as the bottoms, should be dovetailed together to make a satisfactory and good job, though they are often only tongued together. Their size varies, of course, according to circumstances, the standard being 12 inches square and 9 or 10 inches deep.
The same rules apply to lead flats as to gutters, the fells of which are regulated by the bearers, which, of course, are stronger according to the increased bearing.
The rolls, etc, necessitated by the widths of lead or zinc will be dealt with in Chapter XIV (Coverings For Roofs. Lead Work)., on Plumbing and Zincwork.
Gutters behind parapet walls or chimneys are under the same rules with regard to falls, etc., as last described, and are constructed similar to figs. 410 and 411 respectively.
1" scale. Fig 411.
Gutters, owing to their rise up between the roofs, etc, increase in width consequent on the greater distance between the eaves of the roof as they get higher up (see fig. 413); and they must be shown to increase in width on all plans accordingly.
All leadwork in gutters or flats, where traffic would gradually wear it away, should be protected by snom-doards, which consist of arched bearers, across the gutters, supporting laths or lattice-work no more than 3/16 inch apart, running longitudinally with the fall. The bearers must be arched when laid across to allow the water to pass, and the spaces between the laths should never be more than 3/16 inch in width, as snow will get through wider interstices, freeze, expand, and upset the laths, besides forcing the water under the drip or drop, and causing a backing up, and consequently letting the water within the roof when the thaw sets in (vide fig. 413).
Fig. 412. 1/2 Scale.